Adjuvant Chemotherapy For Colon Cancer Research Articles

Siglec9 + tumor-associated macrophages predict prognosis and therapeutic vulnerability in patients with colon cancer

BackgroundSiglec9 has been identified as an immune checkpoint molecule on tumor-associated macrophages (TAMs). Nevertheless, the expression profile and clinical significance of Siglec9 + TAMs in colon cancer (CC) are still not fully understood. MethodsTwo clinical cohorts from distinct medical centers were retrospectively enrolled. Immunohistochemistry and immunofluorescence were conducted to evaluate the infiltration of immune cells. Single-cell RNA sequencing and flow cytometry were utilized to identify the impact of Siglec9 + TAMs on the tumor immune environment, which was subsequently validated through bioinformatics analysis of the TCGA database. Prognosis and the benefit of adjuvant chemotherapy (ACT) were also evaluated using Cox regression analysis and the Kaplan-Meier method. ResultsHigh infiltration of Siglec9 + TAMs was associated with worse prognosis and better benefit from 6-month ACT. Siglec9 + TAMs contributed to immunoevasion by promoting the infiltration of immunosuppressive cells and the dysfunction process of CD8 + T cells. Additionally, high infiltration of Siglec9 + TAMs was associated with the mesenchymal-featured subtype and overexpression of the VEGF signaling pathway, which was validated by the strongest communication between Siglec9 + TAMs and vascular endothelial cells. ConclusionsSiglec9 + TAMs may serve as a biomarker for prognosis and response to ACT in CC. Furthermore, the immunoevasive contexture and angiogenesis stimulated by Siglec9 + TAMs suggest potential treatment combinations for CC patients.

Advances in Adherence Reporting of Resistance Training in a Clinical Trial during Adjuvant Chemotherapy for Colon Cancer.

Detailed reporting of individually tailored exercise prescriptions (ExR x ) used in clinical trials is essential to describe feasibility, tolerability, and efficacy of the intervention and to inform translation to clinical care. This article outlines the methodology used to develop a resistance training (RT) ExR x for people with colon cancer receiving chemotherapy and reports adherence to the randomized controlled trial testing the impact of RT on relative dose intensity of chemotherapy and patient-reported toxicities. Participants randomized to the exercise arm ( n = 90) were included. To promote muscle hypertrophy, the ExR x was twice-weekly, moderate to heavy loads (65%-85% one-repetition maximum), high sets (3-5), and intermediate repetitions (6-10) of five large multijoint movements with adjustable dumbbells. Attendance (achieved frequency) and adherence (achieved volume) were calculated. Group-based trajectory modeling was used to identify clusters of individuals with similar adherence patterns and compared baseline characteristics across adherence groups. The median attendance was 69.1%. Adherence was 60.6% but higher for those receiving 3 versus 6 months of chemotherapy (80.4 vs 47.4%; P < 0.05 ). Participants engaged in a median of 1.4 d of RT each week, lifting 62% of the one-repetition maximum load, for 3.0 sets and 7.5 repetitions per set. Three distinct adherence groups were identified: 13% "nonstarter," 37% "tapered off," and 50% "consistent exercisers." Females were more likely to be in the nonstarter and tapered-off groups. This article outlines suggested methods for reporting ExR x of RT in oncology clinical trials and provides insight into the tolerance of ExR x of RT during chemotherapy treatment for colon cancer. These findings aim to foster constructive dialogue and offer a premise for designing future research to elucidate the benefits of exercise during chemotherapy.

Racial Disparities in Receipt of Guideline-Concordant Care for Early-Onset Colorectal Cancer in the United States.

Young individuals racialized as Black are more likely to die after a colorectal cancer (CRC) diagnosis than individuals racialized as White in the United States. This study examined racial disparities in receipt of timely and guideline-concordant care among individuals racialized as Black and White with early-onset CRC. Individuals age 18-49 years racialized as non-Hispanic Black and White (self-identified) and newly diagnosed with CRC during 2004-2019 were selected from the National Cancer Database. Patients who received recommended care (staging, surgery, lymph node evaluation, chemotherapy, and radiotherapy) were considered to have received guideline-concordant care. Odds ratios (ORs) were adjusted for age and sex. The decomposition method was used to estimate the relative contribution of demographic characteristics (age and sex), comorbidities, health insurance, and facility type to the racial disparity in receipt of guideline-concordant care. The product-limit method was used to evaluate differences in time to treatment between patients racialized as Black and White. Of the 84,882 patients with colon cancer and 62,573 patients with rectal cancer, 20.8% and 14.5% were racialized as Black, respectively. Individuals racialized as Black were more likely to not receive guideline-concordant care for colon (adjusted OR [aOR], 1.18 [95% CI, 1.14 to 1.22]) and rectal (aOR, 1.27 [95% CI, 1.21 to 1.33]) cancers. Health insurance explained 28.2% and 21.6% of the disparity among patients with colon and rectal cancer, respectively. Individuals racialized as Black had increased time to adjuvant chemotherapy for colon cancer (hazard ratio [HR], 1.28 [95% CI, 1.24 to 1.32]) and neoadjuvant chemoradiation for rectal cancer (HR, 1.42 [95% CI, 1.37 to 1.47]) compared with individuals racialized as White. Patients with early-onset CRC racialized as Black receive worse and less timely care than individuals racialized as White. Health insurance, a modifiable factor, was the largest contributor to racial disparities in receipt of guideline-concordant care in this study.

Cumulative incidence of first recurrence after curative treatment of stage I–III colorectal cancer. Competing risk analyses of temporal and anatomic patterns

Background Updated knowledge about the rates of recurrence and time to recurrence following curative treatment of colorectal cancer is essential to secure better patient information on prognosis, to serve as a premise in the discussion on adjuvant chemotherapy, and help to properly scale the intensity and length of follow-up. Methods This is a population-based study investigating aspects on first recurrence after radical treatment of clinical stages I-III of colorectal cancer in Central-Norway during 2001–2015. To reveal any time-trends, data were stratified by the time periods 2001–2005, 2006–2010 and 2011–2015. The cumulative incidence of first recurrence was calculated, treating death of unrelated causes as a competing event. Multivariable Cox analyses were done to calculate cause specific hazard ratios (HR) for risk of recurrence. Results At a minimum follow-up of six years, a first recurrence was detected in 1,113/5,556 patients at risk (20.0%). The recurrence rate was reduced from 23.6% in the first time period, through 20.0% in the second, and to 17.2% in the last, p < 0.001. The reduction applied to all tumor locations, to pathological disease stages II and III, to both gender, across different tumor differentiations, and to both elective and emergency surgery. In multivariable analyses time period, gender, disease stage, and tumor differentiation were significant determinants for risk of recurrence. Conclusions The rate of first recurrence after curative surgery for colorectal cancer was substantially reduced from 2001 to 2015. The reason for the reduction could not be attributed to a single factor only. A combined effect of several incremental improvements, such as an increased use of preoperative radiation for rectal cancers, improved adjuvant chemotherapy for colon cancer, and a reduced proportion of emergency surgery, is suggested.

Association between Ki67 expression and therapeutic outcome in colon cancer.

Ki67 is a commonly used proliferation marker in pathological diagnosis of tumors; however, its prognostic value in colon cancer is controversial. A total of 312 consecutive patients with stage I-III colon cancer who underwent radical surgery with or without adjuvant chemotherapy were included in the present study. Ki67 expression was assessed using immunohistochemistry and was classified according to 25% intervals. The association between Ki67 expression and clinicopathological features was analyzed. Long-term postoperative survival, including disease-free survival (DFS) and overall survival, was calculated, and its association with Ki67 was analyzed. High Ki67 expression (>50%) was associated with improved DFS in patients treated with adjuvant chemotherapy postoperatively, but not in patients who received surgery alone (P=0.138). Ki67 expression was significantly associated with histological differentiation of the tumor (P=0.01), while it was not associated with other clinicopathological factors. Multivariate analysis demonstrated that pathological T and N stage were independent prognostic factors. In conclusion, high Ki67 expression was associated with a good therapeutic outcome in patients receiving adjuvant chemotherapy in colon cancer.

Exploratory randomized phase II trial for optimizing treatment dosage and duration of adjuvant S‐1 plus oxaliplatin in patients with stage III colon cancer: YCOG1402 (SOAP trial)

AbstractIntroductionConventionally, the recommended duration of adjuvant chemotherapy of colon cancer had been 6 months. The IDEA Collaboration suggested that shortening capecitabin and oxaliplatin (CAPOX) adjuvant chemotherapy may be possible. S‐1 and oxaliplatin (SOX) treatment is standard treatment in metastatic colorectal cancer in Japan. The aim of this study was to optimize treatment dosage and duration of adjuvant SOX in stage III colon cancer.MethodsThis trial was as open‐label multi‐center randomized phase II study. Patients with stage III colon cancer were randomly assigned to 3 months or 6 months of adjuvant SOX treatment in different doses: 130 mg/m2 (3 months) or 100 mg/m2 (6 months) of oxaliplatin. The primary endpoint was 3‐year disease‐free survival (DFS) and the null hypothesis for the primary endpoint was that the 3‐year DFS was ≤72% in each arm and was tested with a one‐sided significance level of 10%.ResultsEighty‐two patients were assigned to the 6 months arm and 81 to the 3 months arm. The 3‐year DFS was 75.0% (80% CI 67.95–80.72, p = 0.282) in the 6 months arm and 76.9% (80% CI 70.1–82.38, p = 0.171) in the 3 months arm. Treatment completion rate and relative dose intensity (RDI) were higher in 3 months than 6 months arm. The adverse events (AE) were similar in both arms.ConclusionsThe 3‐year DFS was not significantly superior to null hypothesis in both 3 months and 6 months arms for the stage III colon cancer. Primary endpoint was not achieved. The SOX regimen was not feasible in long‐term outcomes.

Differences in Toxicity Between Ashkenazi and Sephardic Jews With Colon Cancer Treated With Adjuvant Chemotherapy: A Prospective Study.

Ethnicity of cancer patients is increasingly being recognized as an important factor that may influence intergroup variation in toxicity and efficacy of chemotherapy. Data from our institution suggested that differences in chemotherapy-associated toxicity are not limited to distanced ethnic subgroups, such as Caucasians, Afro-Americans, or Asians, but may exist even between two closely related Caucasian ethnic subgroups, such as Ashkenazi and Sephardic Jews. This study aimed to explore differences in severity and frequency of various side effects, including neurotoxicity between patients from the two Jewish subgroups receiving oxaliplatin-containing adjuvant chemotherapy for colon cancer (CC). We recruited 75 patients, with performance status 0-1 and no background of neuropathy between 2012 and 2016. All patients completed a neurotoxicity questionnaire (NQ) and a QoL questionnaire (QoLQ) at baseline and the NQ also at each treatment cycle; during follow up, patients filled out the NQ and the QoLQ every four months for a total of one year. Of the 75 participants, 66 were evaluable for the study including 34 (52%) Sephardic and 32 (48%) Ashkenazi Jews. Grade ≥2 vomiting and diarrhea occurred more often in Sephardic than in Ashkenazi patients (p=0.008 and 0.012, respectively). Of the 66 evaluable patients, 11 (17%) developed grade 3 neurotoxicity; of these, 9 were Sephardic and 2 were Ashkenazi (p=0.028). There were no significant differences in the dynamics of QoL between both subgroups. Sephardic patients receiving oxaliplatin-containing regimens are at an increased risk for neurotoxicity and other side effects as compared to their Ashkenazi counterparts.

Assessment of Attitudes Toward Initiation of Immediate Adjuvant Chemotherapy for Colon Cancer

IntroductionEarly initiation of chemotherapy after surgery for colon cancer has survival benefits. Immediate adjuvant chemotherapy (IAC) involves giving chemotherapy during surgical resection and immediately postoperatively. This novel approach has been shown to be safe, eliminating delays in adjuvant treatment that could increase the risk of micro-metastatic spread. The aim of this study was to assess the willingness of the general public to accept IAC. Materials and methodsBetween March and April 2021, 800 telephone interviews were conducted with a sample of adult New York State residents. The Survey Research Institute of Cornell University conducted all surveys. Kruskal–Wallis, chi-squared, and Fisher’s tests were conducted using R 4.0.2. ResultsThree scenarios were presented: (1) receiving IAC resulting in improved survival and quality of life, (2) finishing chemotherapy earlier without survival impact, and (3) finishing chemotherapy earlier but with possible side effects. Respondents with higher education were more likely to accept (1) & (2), males were more likely to accept (2) & (3), higher income respondents were more likely to accept (1) & (3), and those with more work hours were more likely to accept (2). Lastly, 16% responded they would be very or extremely likely, and 52% respondents would be somewhat likely or likely to accept intraoperative chemotherapy, even if it may not be necessary. ConclusionsRespondents were likely to accept IAC if offered. Given the known risk of delayed adjuvant chemotherapy (AC) in colon cancer, further research is warranted to determine the survival and quality of life (QOL) benefits of IAC.

Targeted maximum likelihood estimation for causal inference in survival and competing risks analysis.

Targeted maximum likelihood estimation (TMLE) provides a general methodology for estimation of causal parameters in presence of high-dimensional nuisance parameters. Generally, TMLE consists of a two-step procedure that combines data-adaptive nuisance parameter estimation with semiparametric efficiency and rigorous statistical inference obtained via a targeted update step. In this paper, we demonstrate the practical applicability of TMLE based causal inference in survival and competing risks settings where event times are not confined to take place on a discrete and finite grid. We focus on estimation of causal effects of time-fixed treatment decisions on survival and absolute risk probabilities, considering different univariate and multidimensional parameters. Besides providing a general guidance to using TMLE for survival and competing risks analysis, we further describe how the previous work can be extended with the use of loss-based cross-validated estimation, also known as super learning, of the conditional hazards. We illustrate the usage of the considered methods using publicly available data from a trial on adjuvant chemotherapy for colon cancer. R software code to implement all considered algorithms and to reproduce all analyses is available in an accompanying online appendix on Github.

The Impact of Colon Cancer Sites on Survival Rates after Curative Resection and Adjuvant Chemotherapy: A SingleCenter Study

Background: Most recent studies indicate that right-sided colon cancer is associated with a significantly higher mortality rate. Multivariate analyses showed that the patient’s age, sex, mode of presentation, co-morbidity, and the stage had significantly influenced their survival. Although the primary tumor location has an impact on the overall survival in metastatic settings, the laterality of early-stage colon cancer might also affect the disease-free survival and determine the duration of adjuvant chemotherapy for each side. This study aimed to compare overall survival and disease-free survival between left-sided and right-sided high-risk stage II and stage III colon cancer in patients from a single institute. Methods: This retrospective cohort study was conducted between January 2004 and December 2017. Data on 153 patients who underwent curative resection and adjuvant chemotherapy for colon cancer were retrieved from an existing database. Results: We found that the five-year disease-free survival rates were 63.20% for left-sided colon cancer and 51.11% for right-sided colon cancer (P-value &lt; 0.05). The five-year overall survival rates were 66.98% for left-sided colon cancer and 57.77% for right-sided colon cancer (P-value 0.063). The right-sided primary tumor location was associated with a significantly higher mortality rate (HR: 2.28; 95%CI 1.38–5.8; P-value: 0.004). Conclusion: The results of this study confirmed that patients with high-risk stage II and stage III colon cancer who had right-sided tumors were significantly more likely to have decreased disease-free survival and overall survival. Further prospective studies should focus on tumor genetics and proper durations of adjuvant chemotherapy to maximize the benefit of treatment with acceptable toxicity.

High Expression of CUL9 Is Prognostic and Predictive for Adjuvant Chemotherapy in High-Risk Stage II and Stage III Colon Cancer.

Simple SummaryThis retrospective study evaluated the clinical implications of CUL9 expression on the prognosis and the predictive value for postoperative adjuvant chemotherapy in consecutive patients with colon cancer. Among all 1078 patients, high expression of CUL9 was an independent prognostic factor on disease-free survival and overall survival. Prognostic biomarkers are keys to the risk stratification of patients and the decision to recommend adjuvant chemotherapy. Among 564 patients with high-risk stage II and stage III disease who were recommended to receive the standard 6 months of chemotherapy, those with high CUL9 expression from the full dose group had better disease-free survival than those from the reduced dose group. A test for the interaction between CUL9 expression and the treatment reached significance and was not confounded by T stage, N stage and histopathological grade. This indicated that CUL9 expression may further filter those patients to identify truly high-risk cases that benefit from the full dose of the standard 6 months of chemotherapy.We evaluated the clinical implications of CUL9 expression on the prognosis and the predictive value for adjuvant chemotherapy in colon cancer. A total of 1078 consecutive patients treated with radical resection from 2008 to 2012 were included. Formalin-fixed, paraffin-embedded specimens were used as immunohistochemistry (IHC) for CUL9. For all patients, high expression of CUL9 was identified as an independent prognostic factor for overall survival (HR = 1.613, 95% CI 1.305–1.993, p < 0.001) and disease-free survival (HR = 1.570, 95% CI 1.159–2.128, p = 0.004). The prognostic value of high CUL9 expression was confirmed in an independent validation cohort from the GEO database. The efficacy of adjuvant chemotherapy was analyzed among patients with high-risk stage II and stage III disease. Those with high CUL9 expression from the full dose group had better disease-free survival (HR = 0.477, 95% CI 0.276–0.825, p = 0.006) than those from the reduced dose group. The interaction test between CUL9 expression and the treatment reached significance and was not confounded by T stage, N stage and histopathological grade. In general, high expression of CUL9 was an independent prognostic factor in patients with colon cancer. In those with high-risk stage II and stage III disease, high expression of CUL9 was associated with the benefit from standard 6-months adjuvant chemotherapy regimens.

The Prognostic Value of Adjuvant Chemotherapy in Colon Cancer With Solitary Tumor Deposit.

PurposeThe aim of this study is to investigate the survival benefit of adjuvant chemotherapy in patients with colon cancer with the solitary tumor deposit (TD).MethodsThe primary study outcomes used in this study were colon cancer–specific survival (CSS) and overall survival (OS). The differences of the distribution of categorical variables in patients with colon cancer with the solitary TD according to adjuvant chemotherapy administration were tested using the Pearson’s chi-square test. The Kaplan–Meier method was utilized to evaluate CSS and OS. Hazard ratio (HR) and 95% confidence interval (CI) were calculated on the basis of Cox regression models to assess the prognostic value of different demographic and clinicopathological characteristics.ResultsA total of 877 patients with TanyN1cM0 colon cancer with solitary TD were identified in our analysis. It was found that OS (75.4% vs. 42.8% for 5-year OS rate, p < 0.001) and CSS (82.9% vs. 69.3% for 5-year CSS rate, p < 0.001) of patients with colon cancer with adjuvant chemotherapy administration were significantly better than those without adjuvant chemotherapy administration. Multivariate Cox survival analyses revealed that the overall and colon cancer–specific mortality risks of patients with adjuvant chemotherapy administration were decreased by 64.4% (HR = 0.356, 95% CI = 0.265–0.479, p < 0.001) and 57.4% (HR = 0.426, 95% CI = 0.286–0.634, p < 0.001) compared with those without adjuvant chemotherapy administration, respectively.ConclusionsAdjuvant chemotherapy administration could significantly improve OS and CSS in patients with colon cancer with the solitary TD. This is the first study to investigate and demonstrate the survival benefit of adjuvant chemotherapy in patients with colon cancer with the solitary TD.

Cost-effectiveness of adjuvant chemotherapy for patients with high-risk stage II and stage III colon cancer in South Africa.

6599 Background: Colon cancer (CC) incidence is rising globally, and case fatality rates are greatest in low-income settings, such as South Africa (SA). Adjuvant chemotherapy is standard of care for high-risk stage II and stage III CC in the US. We evaluated the cost-effectiveness of adjuvant chemotherapy for CC in SA public hospitals. Methods: We developed a decision-analytic Markov model comparing lifetime costs and outcomes for 60-year-old high-risk stage II and stage III CC patients treated in a SA public hospital with no adjuvant chemotherapy, versus: capecitabine and oxaliplatin (CAPOX) for 3 or 6 months or capecitabine for 6 months. High-risk stage II was defined as ≥1 of: T4 disease; poorly differentiated tumor; lymphovascular/perineural invasion; &lt;12 lymph nodes dissected, bowel obstruction/perforation. Transition probabilities were derived from clinical trials estimating toxicity, disease recurrence, and survival. Costs from a SA societal perspective and utility estimates were obtained from literature and local expert opinion. The primary outcome was the incremental cost-effectiveness ratio (ICER) in international dollars (I$) per disability-adjusted life year (DALY) averted, with a willingness-to-pay (WTP) threshold equal to 2021 GDP/capita of SA (I$13,764). Results: CAPOX for 3 months was the cost-effective strategy for stage III CC at a lifetime cost of I$5,284 and 5.55 DALYs averted, compared to no adjuvant treatment. All other strategies were absolutely dominated. For high-risk stage II CC, CAPOX for 3 months was the cost-effective strategy (ICER = I$711/DALY averted). No adjuvant chemotherapy was on the efficiency frontier, with a lower lifetime cost, but no DALYs averted. The results of one-way deterministic sensitivity analyses showed that the model is most sensitive to CC recurrence rate. In a probabilistic sensitivity analysis, CAPOX for 3 months was optimal in 88% of iterations for high-risk stage II CC and 79% of iterations for stage III CC. Conclusions: CAPOX for 3 months is the cost-effective adjuvant treatment for high-risk stage II and stage III CC in SA public hospitals. This strategy offers the highest quality of life benefit for the lowest cost and is well within the WTP threshold for SA. The optimal strategy in other settings will vary according to local WTP thresholds. Base case estimates of cost-effectiveness, in order of cost. [Table: see text]

Cost-effectiveness of DPYD Genotyping Prior to Fluoropyrimidine-based Adjuvant Chemotherapy for Colon Cancer

BackgroundAdjuvant fluoropyrimidine-based chemotherapy substantially reduces recurrence and mortality after resection of stage 3 colon cancer. While standard doses of 5-fluorouracil and capecitabine are safe for most patients, the risk of severe toxicity is increased for the approximately 6% of patients with dihydropyimidine dehydrogenase (DPD) deficiency caused by pathogenic DPYD gene variants. Pre-treatment screening for pathogenic DPYD gene variants reduces severe toxicity but has not been widely adopted in the United States. MethodsWe conducted a cost-effectiveness analysis of DPYD genotyping prior to fluoropyrimidine-based adjuvant chemotherapy for stage 3 colon cancer, covering the c.1129-5923C>G (HapB3), c.1679T>G (*13), c.1905+1G>A (*2A), and c.2846A>T gene variants. We used a Markov model with a 5-year horizon, taking a United States healthcare perspective. Simulated patients with pathogenic DPYD gene variants received reduced-dose fluoropyrimidine chemotherapy. The primary outcome was the incremental cost-effectiveness ratio (ICER) for DPYD genotyping. ResultsCompared with no screening for DPD deficiency, DPYD genotyping increased per-patient costs by $78 and improved survival by 0.0038 quality-adjusted life years (QALYs), leading to an ICER of $20,506/QALY. In 1-way sensitivity analyses, The ICER exceeded $50,000 per QALY when the cost of the DPYD genotyping assay was greater than $286. In probabilistic sensitivity analysis using a willingness-to-pay threshold of $50,000/QALY DPYD genotyping was preferred to no screening in 96.2% of iterations. ConclusionAmong patients receiving adjuvant chemotherapy for stage 3 colon cancer, screening for DPD deficiency with DPYD genotyping is a cost-effective strategy for preventing infrequent but severe and sometimes fatal toxicities of fluoropyrimidine chemotherapy.

Are patients living far from hospital at higher risk of late adjuvant chemotherapy for colon cancer?

Late adjuvant chemotherapy (aCT) administration after colectomy (>56 d) is known to be associated with impaired prognosis. We aim to identify risk factors associated with late aCT, especially the travel time between patients' home and hospital. We performed a retrospective monocentre cohort study. Patients included had a colectomy for a stage III or high risk stage II colon cancer between 2009 and 2015 performed at a French university hospital. Risk factors for late aCT were identified using a fractional polynomial logistic regression. Ninety-four patients were included. The risk of late aCT was associated with travel time length, emergent colectomy, the need for scheduled care before aCT, and length of time between colectomy and postoperative multidisciplinary meeting advising aCT. Our study suggests that, in patients with colon cancer, factors unrelated to disease severity and complexity could be associated with a higher risk of late aCT.

Current Perspectives on the Importance of Pathological Features in Prognostication and Guidance of Adjuvant Chemotherapy in Colon Cancer.

There is not a clear consensus on which pathological features and biomarkers are important in guiding prognosis and adjuvant therapy in colon cancer. The Pathology in Colon Cancer, Prognosis and Uptake of Adjuvant Therapy (PiCC UP) Australia and New Zealand questionnaire was distributed to colorectal surgeons, medical oncologists and pathologists after institutional board approval. The aim of this study was to understand current specialist attitudes towards pathological features in the prognostication of colon cancer and adjuvant therapy in stage II disease. A 5-scale Likert score was used to assess attitudes towards 23 pathological features for prognosis and 18 features for adjuvant therapy. Data were analysed using a rating scale and graded response model in item response theory (IRT) on STATA (Stata MP, version 15; StataCorp LP). One hundred and sixty-four specialists (45 oncologists, 86 surgeons and 33 pathologists) participated. Based on IRT modelling, the most important pathological features for prognosis in colon cancer were distant metastases, lymph node metastases and liver metastases. Other features seen as important were tumour rupture, involved margin, radial margin, CRM, lymphovascular invasion and grade of differentiation. Size of tumour, location, lymph node ratio and EGFR status were considered less important. The most important features in decision making for adjuvant therapy in stage II colon cancer were tumour rupture, lymphovascular invasion and microsatellite instability. BRAF status, size of tumour, location, tumour budding and tumour infiltrating lymphocytes were factored as lesser importance. Biomarkers such as CDX2, EGFR, KRAS and BRAF status present areas for further research to improve precision oncology. This study provides the most current status on the importance of pathological features in prognostication and recommendations for adjuvant therapy in Australia and New Zealand. Results of this nationwide study may be useful to help in guiding prognosis and adjuvant treatment in colon cancer.

Evaluation of stromal cell infiltration in the tumor microenvironment enable prediction of treatment sensitivity and prognosis in colon cancer

Current clinical factors for screening candidates that might benefit from adjuvant chemotherapy in colon cancer are inadequate. Tumor microenvironment, especially the stromal components, has the potential to determine treatment response. However, clinical translation of the tumor-associated stromal characterization into a practical biomarker for helping treatment decision has not been established. Using machine learning, we established a novel 31-gene signature, called stromal cell infiltration intensity score (SIIS), to distinguish patients characterized by the enrichment of abundant stromal cells in five colon cancer datasets from GEO (N = 990). Patients with high-SIIS were at higher risk for recurrence and mortality, and could not benefit from adjuvant chemotherapy due to their intrinsic drug resistance; however, the opposite was reported for patients with low-SIIS. The role of SIIS in detection of patients with high stromal cell infiltration and reduced drug efficiency was consistently validated in the TCGA-COAD cohort (N = 382), Sun Yat-sen University Cancer Center cohort (N = 30), and could also be observed in TCGA pan-cancer settings (N = 4898) and four independent immunotherapy cohorts (N = 467). Based on multi-omics data analysis and the CRISPR library screen, we reported that lack of gene mutation, hypomethylation in ADCY4 promoter region, activation of WNT-PCP pathway and SIAH2-GPX3 axis were potential mechanisms responsible for the chemoresistance of patients within high-SIIS group. Our findings demonstrated that SIIS provide an important reference for those making treatment decisions for such special patients.

Assessing the representativeness of trial populations for contemporary real-world cancer patients: A case study of adjuvant chemotherapy for colon cancer.

306 Background: Randomized controlled trials are the gold standard for assessing the efficacy of new cancer therapies and are required for marketing approval. However, participants enrolled into trials are often not representative of the more diverse populations in whom treatment will ultimately be delivered. Real-world data can be used to potentially bridge this gap by evaluating the effectiveness and safety of therapies in more generalizable populations. In this study, we describe differences in demographic and clinical characteristics between participants enrolled in a phase III trial of adjuvant chemotherapy for colon cancer and a contemporary comparator cohort using structured oncology electronic medical records (EMR) data. Methods: We drew upon publications from the Multicenter International Study of Oxaliplatin/5 Fluorouracil/Leucovorin in the Adjuvant Treatment of Colon Cancer (MOSAIC) recruiting patients primarily from Western Europe with stage II or III colon cancer from October 1998-January 2001. This trial established FOLFOX (oxaliplatin + 5-FU) as the standard of care over 5FU alone in treating stage III colon cancer and led to US marketing approval. For comparison, we identified patients diagnosed with stage II or III colon cancer (September 2014-2020) who received FOLFOX in the IQVIA US Oncology EMR database via E360, IQVIA’s Real World Discovery and Analytics platform. In the two populations, we described distributions of prognostic factors including age, sex, stage of disease, body mass index (BMI), and Eastern Cooperative Group (ECOG) performance status. Results: The MOSAIC trial included 2,246 participants; we identified 4,566 patients starting FOLFOX in the EMR comparator. Median age was similar: 61 versus 62 years, but the range differed (19-75 years versus 18-85 years) in the trial and EMR comparator, respectively. Female sex was similar at 44% and 48%, while the proportion of patients with stage III disease differed considerably at 60% and 84% for trial and EMR comparator, respectively. Half (51%) of all EMR patients were missing ECOG status; among those with a reported ECOG status, 96% had a score of 0-1, while 87% of trial participants had an ECOG of 0-1. BMI was missing in 34% of patients in the EMR comparator; among those with a reported BMI, 28% had a BMI &lt; 25, while 54% of trial participants had a BMI &lt; 25. Conclusions: Colon cancer patients receiving FOLFOX in an EMR comparator had a similar age and sex distribution as MOSAIC trial participants, but were more likely to have stage III disease. Missing ECOG and BMI data were common in the EMR comparator, which limited comparisons. Structured oncology EMR data represent an important resource for generating real-world evidence; future data enrichment efforts focused on critical patient-level variables via unstructured EMR extraction may improve data completeness and quality.

Sustainable Clinical Development of Adjuvant Chemotherapy for Colon Cancer.

Numerous clinical studies in an adjuvant setting have been conducted and the combination therapy of 5‐fluorouracil and oxaliplatin has been established as the standard treatment for Stage III and as an option for high‐risk Stage II patients. Biologics such as bevacizumab and antiepidermal growth factor receptor antibodies have failed to show additional survival benefits. The indication of adjuvant chemotherapy has been determined according to the pathological stage. Nevertheless, a pathological diagnosis does not necessarily result in selection of the optimal treatment. To improve treatment decisions, many trials have aimed to stratify patients into treatment groups using genomic testing. Recently, gene signature, Immunoscore, and circulating tumor DNA (ctDNA) assays have been reported and among them, ctDNA was shown to be a promising accurate predictive marker for recurrence. Treatment of ctDNA‐positive patients with aggressive chemotherapy may reduce recurrence rates. The ultimate goal is to accurately predict the risk of recurrence and to prevent recurrence in colon cancer patients. In this review we focus on the clinical development of adjuvant chemotherapy and stratification of patients according to risk of recurrence and the future direction of adjuvant chemotherapy.

Abstract CT251: MEDOCC-CrEATE trial in progress: effectiveness of adjuvant chemotherapy in stage II colon cancer patients with positive circulating tumor DNA

Abstract Background Accurate detection of patients with minimal residual disease (MRD) after resection of localized colon cancer remains an unmet clinical need as these patients might benefit from adjuvant chemotherapy (ACT). For stage II colon cancer, ACT is only indicated in patients with a pT4 tumor without a deficient mismatch repair system (dMMR), according to Dutch guidelines. However, recurrence rate (RR) in stage II colon cancer is still 15-20%. Circulating tumor DNA (ctDNA), consisting of small fragments of DNA containing tumor-specific mutations, has been shown to be a promising biomarker for MRD and a strong predictor for recurrent disease when detectable after resection. The MEDOCC-CrEATE trial investigates how many stage II colon cancer patients with detectable ctDNA after surgery will accept ACT and whether ACT reduces RR in these patients. Methods The MEDOCC-CrEATE study follows the ‘trials within cohorts' (TwiCs) design. Patients with colorectal cancer are included in the Prospective Dutch ColoRectal Cancer (PLCRC) cohort study and give informed consent for collection of clinical data and biomaterials, including tissue and blood samples. Additionally, patients are invited to give their consent for future randomization without being informed when allocated to the control group receiving standard of care. In MEDOCC-CrEATE 1320 stage II colon cancer patients without an indication for ACT will be included and randomized 1:1 into an experimental and a control arm. In the experimental arm, tissue and blood samples are analyzed after surgery for tissue-informed detection of plasma ctDNA, using the PGDx elio™ Platform. Patients with detectable ctDNA after surgery will be offered ACT consisting of 8 cycles of capecitabine plus oxaliplatin. Patients in the experimental arm without detectable ctDNA and patients in the control arm receive standard follow-up. The primary endpoint is the proportion of patients accepting ACT when ctDNA is detectable after resection. Most important secondary endpoint is 2-year RR, but also includes 5-year RR, disease free and overall survival, time to recurrence, quality of life and cost-effectiveness of the ctDNA-based treatment strategy. Data will be analyzed by intention to treat. To our knowledge, MEDOCC-CrEATE is the first trial in which a ctDNA guided strategy for adjuvant chemotherapy in colon cancer is investigated. The first patient was enrolled in August 2020. MEDOCC-CrEATE is now open for inclusion in 8 hospitals in the Netherlands. So far, 9 patients have been randomized. The number of participating hospitals will be expanded to 20-25 hospitals to include all 1320 patients within 3 years. MEDOCC-CrEATE has been registered in the Netherlands Trial Register: NL6281/NTR6455. Citation Format: Suzanna J. Schraa, Karlijn L. Van Rooijen, Dave E. Van Der Kruijssen, Carmen Rubio Alarcón, Jillian Phallen, John Simmons, Sam Angiuoli, Amy E. Greer, Veerle M. Coupé, Helma M. Van Grevenstein, Sjoerd Elias, Helena M. Verkooijen, Miranda M. Van Dongen, Linda J. Bosch, Daan Van Den Broek, Gerrit A. Meijer, Victor E. Velculescu, Remond J. Fijneman, Geraldine R. Vink, Miriam Koopman. MEDOCC-CrEATE trial in progress: effectiveness of adjuvant chemotherapy in stage II colon cancer patients with positive circulating tumor DNA [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT251.